GoogleContainerTools/skaffold · error

evaluating custom template component

Error message

evaluating custom template component: %w

What it means

One of the component taggers failed while generating its tag string during custom template evaluation. After all taggers are collected, `EvaluateComponents` calls each tagger's `GenerateTag(ctx, image)`; any failure is wrapped with this message naming none of them directly but wrapping the underlying cause. The template is never executed.

Solutions

1. Read the wrapped cause to identify which component failed and why
2. For GIT component: ensure the workspace is a git repo with at least one commit (git init && git commit)
3. For DIGEST/SHA components: ensure the image was built/pushed before tagging
4. Verify git is installed and accessible on PATH

Example fix

// before: not a git repo, GIT tagger fails
skaffold dev
// after
git init && git add -A && git commit -m init
skaffold dev

// pre-check environment for GIT component
if fieldsContain(tmpl, "GIT") {
    if _, err := exec.LookPath("git"); err != nil {
        return errors.New("git not on PATH; required by GIT tag component")
    }
    if _, err := git.ExecCommand(ctx, nil, "rev-parse", "HEAD"); err != nil {
        return errors.New("not a git repository with commits")
    }
}

customMap, err := tag.EvaluateComponents(ctx, t, image)
if err != nil {
    var cause error
    if errors.As(err, &cause) {
        log.Errorf("component failed: %v", cause) // e.g. git describe error
    }
    return fmt.Errorf("ensure git repo exists and image is built: %w", err)
}

When it happens

Trigger: During `GenerateTag`, a component tagger (e.g. GIT, SHA, DIGEST) errors — e.g. `git describe` fails because the workspace is not a git repo, or digest computation fails because the image isn't available.

Common situations: GIT component used outside a git repository or with no commits; SHA/digest tagger used before the image is built/pushed; git binary missing in the environment; shallow clone without tags.

Related errors

• executing template
• getting git status
• getting tags
• no tagger available for component %+v
• parsing template

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/fe1b3f7add827ea9. Report an issue: GitHub.

Appendix: source

Thrown at pkg/skaffold/tag/custom_template.go:101

			gitTagger, _ := NewGitCommit("", "", false)
			taggers[field] = gitTagger
		case "DATE":
			taggers[field] = NewDateTimeTagger("", "")
		case "SHA":
			taggers[field] = &ChecksumTagger{}
		case "INPUT_DIGEST":
			inputDigestTagger, _ := NewInputDigestTagger(t.RunCtx, graph.ToArtifactGraph(t.RunCtx.Artifacts()))
			taggers[field] = inputDigestTagger
		default:
			return nil, fmt.Errorf("no tagger available for component %+v", field)
		}
	}

	customMap := map[string]string{}
	for k, v := range taggers {
		tag, err := v.GenerateTag(ctx, image)
		if err != nil {
			return nil, fmt.Errorf("evaluating custom template component: %w", err)
		}
		customMap[k] = tag
	}
	return customMap, nil
}

// ParseCustomTemplate is a simple wrapper to parse an custom template.
func ParseCustomTemplate(t string) (*template.Template, error) {
	return template.New("customTemplate").Parse(t)
}

// ExecuteCustomTemplate executes a customTemplate against a custom map.
func ExecuteCustomTemplate(customTemplate *template.Template, customMap map[string]string) (string, error) {
	var buf bytes.Buffer
	log.Entry(context.TODO()).Debugf("Executing custom template %v with custom map %v", customTemplate, customMap)
	if err := customTemplate.Execute(&buf, customMap); err != nil {
		return "", fmt.Errorf("executing template: %w", err)
	}

View on GitHub (pinned to a1189de023)